Half-size Batches?

[agentbud]

This is one of those questions that I am pretty sure of the answer but want to hear from people have actually done it to get any tips or pointers. I normally brew 5 gallon batches so all my equipment is geared toward 5 gallon brews (35L brewzilla, 30L Speidel fermenters and 5 gallon kegs). I want to start brewing some half batches (2.5 gallon) for when I am testing a new recipe. I know that recipes will scale down (ie just half everything) and I know I can do smaller batches in the Brewzilla. My main question is regarding the larger fermenters and kegs, specifically about the extra headspace. I have good processes in place to limit O2 exposure during kegging. Any tips/pointers/downsides to putting 2.5 gal batches in fermenters and kegs designed for 5 gal?

 

[CascadesBrewer]

Any tips/pointers/downsides to putting 2.5 gal batches in fermenters and kegs designed for 5 gal?

Nope, but I do brew quite a few 2.5 gallon batches. Your full size fermenter should be fine. There are some reasonably priced small fermenters like the Fermonster (I have a pair of 3 gallon) and Speidel. I also have a 3.5 gallon brew bucket.

Again, your 5 gallon kegs will work fine. You will end up using more CO2 vs a smaller keg, but maybe just an extra $1 per batch. For me the killer would have been room in my kegerator. I got a pair of 10L Torpedo kegs that stack into almost the same area as a 5 gallon keg. The downside is the $100-ish price tag per keg. Kegland does sell the 8L Oxebar kegs that have potential.

Another option might be to ferment and serve from a 5 gallon keg. That way you know the keg is fully purged of oxygen, and you could offset the CO2 usage needed to purge and carbonate in a 5 gallon keg. I have done this with a 3 gallon batch, and it worked out well.

 

[Yesfan]

If you have ever wondered about pressurized fermentations, you could certainly use your 5 gallon kegs for those 2.5 gallon batches. All you'd need is a floating diptube and a spunding valve.

I agree with Cascades about the 2.5 gallon Torpedo kegs. I love mine.

 

[ninkwood]

Nope, but I do brew quite a few 2.5 gallon batches. Your full size fermenter should be fine. There are some reasonably priced small fermenters like the Fermonster (I have a pair of 3 gallon) and Speidel. I also have a 3.5 gallon brew bucket.

Again, your 5 gallon kegs will work fine. You will end up using more CO2 vs a smaller keg, but maybe just an extra $1 per batch. For me the killer would have been room in my kegerator. I got a pair of 10L Torpedo kegs that stack into almost the same area as a 5 gallon keg. The downside is the $100-ish price tag per keg. Kegland does sell the 8L Oxebar kegs that have potential.

Another option might be to ferment and serve from a 5 gallon keg. That way you know the keg is fully purged of oxygen, and you could offset the CO2 usage needed to purge and carbonate in a 5 gallon keg. I have done this with a 3 gallon batch, and it worked out well.

I have 4x 8L oxebar kegs that I use for this exact purpose. I originally bought them as a cheaper transition to kegging. I find them frustrating at times. Firstly, I no longer trust the prv's as I constantly had issues with gas leaks and have capped them all off with regular bottle caps. Secondly, the silicone elbows that connect the liquid ball lock to the dip tube are not very durable, and occasionally leak inside the keg causing foaming or poor quality pours. In short, I never put beer in these things that I've worked really hard on or that I cherish - but they're absolutely fantastic for small test batches. My new process when developing a recipe is to brew an 8L or 16L final batch size using a brewzilla gen 4 35L and a fermzilla all rounder FV. The Brewzilla doubles as my HLT on my 3V setup that I use for my "serious" brews. I've even used one of the oxebars as a fermenter for smaller 5-6L batches of extra-experimental brews. The oxebars are great for this. They fit into tight spots inside my keezer and they're more convenient than bottling. They're also great for transporting beer to visit friends and family a few hours away. They're finicky and shouldn't be relied upon to keep your precious beer safe, but I'm not very sentimental about test batches, and they have some decent upside as well. Though ultimately if money is no concern 2.5G cornys would get my vote. Hope this helps!

 

[kevin58]

I scaled down recently from brewing on an Anvil Foundry 10.5 to the Foundry 6.5 (5 gal to 2.5 gal batches) and bought a 4 gallon fermenter and two 3 gallon corny kegs. The fermenter was on sale by the manufacturer and the kegs I found on FB marketplace.

 

[jdauria]

I sold my Anvil Foundry 10.5 last year and downsized to the 6.5 to do 2.5 gallon batches, due to a health reason forcing me to reduce my alcohol intake. Even with 2.5 gallons, most goes to family, friends or comps, and I drink maybe 6 pints of it. Anyway, what I did was buy a few 2.5-3 gallon Better Bottle carboys and a few 2.5 gallon kegs. But when those are full, I ferment in 5 gallon ones without any problems and use 5 gallon kegs without an issue either. Only thing I would not do in a 5 gallon fermenter is long term aging of a big beer, too much head space.

 

[ninkwood]

The added headspace might be a benefit for those of us without access to concentrated o2... More oxygen in the fermenter for the yeast to use. I'm sure there are some downsides as well that I'm glossing over.